// mutex.hpp
/*
 *  Copyright (c) 2018-present, Leigh Johnston.
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 *     * Neither the name of Leigh Johnston nor the names of any
 *       other contributors to this software may be used to endorse or
 *       promote products derived from this software without specific prior
 *       written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 *  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 *  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 *  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 *  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#pragma once

#include "neolib.hpp"
#include <mutex>
#include <memory>
#include "null_mutex.hpp"
#include "lifetime.hpp"

namespace neolib
{
    template<class Mutex>
    class destroyable_mutex_lock_guard
    {
    public:
        typedef Mutex mutex_type;
        typedef std::shared_ptr<mutex_type> shared_mutex_type;
    public:
        explicit destroyable_mutex_lock_guard(mutex_type& aMutex) :
            iMutex{ aMutex }, iMutexDestroyed{ aMutex }, iLocked{ false }
        {
            iMutex.lock();
            iLocked = true;
        }
        explicit destroyable_mutex_lock_guard(shared_mutex_type& aMutex) :
            iMutex{ *aMutex }, iMutexDestroyed{ *aMutex }, iLocked{ false }
        {
            iMutex.lock();
            iLocked = true;
        }
        destroyable_mutex_lock_guard(mutex_type& aMutex, std::adopt_lock_t) :
            iMutex{ aMutex }, iMutexDestroyed{ aMutex }, iLocked{ true }
        {
        }
        destroyable_mutex_lock_guard(shared_mutex_type& aMutex, std::adopt_lock_t) :
            iMutex{ *aMutex }, iMutexDestroyed{ *aMutex }, iLocked{ true }
        {
        }
        ~destroyable_mutex_lock_guard() noexcept
        {
            unlock();
        }
        destroyable_mutex_lock_guard(const destroyable_mutex_lock_guard&) = delete;
        destroyable_mutex_lock_guard& operator=(const destroyable_mutex_lock_guard&) = delete;
    public:
        void unlock()
        {
            if (iLocked && !iMutexDestroyed)
            {
                iMutex.unlock();
                iLocked = false;
            }
        }
    private:
        mutex_type& iMutex;
        destroyed_flag iMutexDestroyed;
        bool iLocked;
    };
}
